Centering devices for endless filter belt

ABSTRACT

A pair of opposedly arranged belt-centering devices for belttype vacuum drum filter apparatus, each device engaging a respective beaded side edge portion of the filter belt, each device having an assembly of a pair of bead gripping glide shoes biased towards each other while slidably engaging opposedly arranged tracks on the associated bead, which assembly is also biased in a direction laterally away from the belt and from the associated bead.

United States Patent Barnebl et al.

[ *Feb. 15, 1972 CENTERING DEVICES FOR ENDLESS FILTER Inventors: August C. Barnebl, Stamford; Franz Bliem; Ernst R. Kus, both of 'Norwalk, all of Conn.

Dorr-Oliver Conn.

Assignee: Incorporated, Stamford,

Notice: The portion of the term of this patent subsequent to Mar 31, 1987, has been disclaimed.

Filed: Mar. 26, 1970 Appl. No.: 22,801

Related US. Application Data Continuation-impart of Ser. No. 700,579, Jan. 25, 1968, Pat. No. 3,503,517.

US. Cl ..2l0/401 Int. Cl ..B0ld 33/14 Field of Search ..2 10/400, 401 402, 403, 404

[56] References Cited UNITED STATES PATENTS 3,077,990 2/1963 Peterson ..2 10/401 3,288,298 1 H1966 Daugherty et al. ..2l0/40l 3,503,517 3/1970 Bamebl et al ..210/401 Primary ExaminerReuben Friedman Assistant Examiner-T. A. Granger Attorney-T. M. Jablon, D. M. Mezzapelle and J. Dennis Malone ABSTRACT A pair of opposedly arranged belt-centering devices for belttype vacuum drum filter apparatus, each device engaging a respective beaded side edge portion of the filter belt, each device having an assembly of a pair of bead gripping glide shoes biased towards each other while slidably engaging opposedly arranged tracks on the associated bead, which assembly is also biased in a direction laterally away from the belt and from the associated bead.

39 Claims, 36 Drawing Figures FIG.

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IN VEN TORS.

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CENTERING DEVICES FOR ENDLESS FILTER BELT This is a continuation-in-part of an application by Barnebl, Bliem and Kus. Ser. No. 700,579 filed Jan. 25, 1968, now US. Pat. No. 3,503,517.

This invention relates to rotary drum filters of the type that is equipped with an endless travelling filter belt.

In a belt-type vacuum drum filter unit, a horizontal filter drum is mounted on a support structure, and drive means are provided for rotating the drum through a filtration cycle, with the lower portion of the drum immersed in a bath of slurry. An endless filter belt surrounds a major portion of the circumference of the drum so that the belt is moved by the rotation of the drum. During the filtration cycle, a layer or cake of slurry solids from the bat is collected and held on the filter belt by vacuum, to be discharged after the belt leaves the upper portion of the drum. That is to say, the belt is guided away from the upper portion of the drum and over a cake discharge roller, and then back onto the lower portion of the drum where the layer of solids is collected from the bath.

This invention is concerned with improvements in tracking or centering devices for the filter belt, of the type that exerts transverse stretch or tension upon the filter belt after it leaves the filter drum, in such a manner that the filter belt is kept wrinkle free as well as in substantial center alignment with the filter drum.

A pair of such opposedly arranged cooperating tracking devices engage the beaded edge portions of the filter bath, exerting pull transversely of the belt in directions opposite to each other, and substantially perpendicular to the edge portions of the belt. The bead gripping head portion in each of these tracking devices is capable of releasing the associated bead of the belt in case of excessive lateral pull developing from excessive deviation of the belt. An example of such belt tracking devices is found for instance in the US. Fat. to Petersen No. 3,077,990 and US. Pat. to DaughertyNo. 3,288,298 disclosing a pair of opposedly arranged belt gripping devices each having track rollers engaging respective beads or edge portions of the belt.

This invention is related to the aforementioned copending application, Ser. No. 700,579, now U.S. Pat. No. 3,503,517 in that it employs elongate glide shoes engaging the beaded edge portion of the belt, avoiding the use of the track rollers and the concentrated roller pressure acting on the tracks with resulting wear and tear on the belt, while discouraging derailment of the rollers from the tracks.

The copending application discloses a pair of opposedlyarranged belt tensioning devices wherein a pair of glide shoes are biased toward each other, which assembly of glide shoes is mounted upon the end of a rod which extends laterally away from the belt, and in perpendicular relationship to the glide shoes and to the bead. The rod is supported for rotational as well as axial movement, and is biased in axial outward direction laterally away from the belt.

The copending application discloses the glide shoes hinged together, allowing the glide shoes to adjust themselves to the path of the bead, due to coaction with the axial and rotational movements of the rod in a tubular guide.

According to one aspect of the present improvements the glide shoe assembly is capable of bodily or floating movement in a direction substantially perpendicular to the plane of the filter belt providing self-adjustability.

In one embodiment, a tubular guide for the rod that carries the guide shoe assembly, is mounted for floating movement upon the outer end of a swingable member, the plane of its swinging movement being transverse of the plane of the belt.

In another embodiment, the rod is mounted for angular or swinging movement of the rod, the plane of the swinging movement being perpendicular to the plane of the belt.

Other improvements are concerned with a variety of glide shoe assemblies.

Other features and advantages will hereinafter appear.

FIG. 1 is a perspective view of a belt-type rotary vacuum drum filter, showing two cooperating belt tensioning devices engaging the beaded edge portions of the filter belt.

FIG. 2 is a greatly enlarged plan view of the belt tensioning device, taken on line 22 in FIG. 1.

FIG. 3 is a side view of the tensioning device taken on line 3-3 in FIG. 2, showing belt gripping glide shoe members hinged together and biased towards each other.

FIG. 3a is a fragmentary side view similar to FIG. 3, showing a different hinge arrangement.

FIG. 3b is a plan view taken on line 3b3b in FIG. 3a.

FIG. 4 is a cross-sectional view of the filter belt.

FIG. 5 is a perspective view of a belt-type vacuum drum filter equipped with a pair of different beit tracking devices.

FIG. 6 is a greatly enlarged plan view of the devices shown in FIG. 5, featuring a floating arrangement of the glide shoe assembly.

FIG. 7 is a side view of the device taken on line 7-7 in FIG. 6.

FIG. 8 is a fragmentary end view taken on line 88 of FIG. 6, showing the bead gripping function of the glide shoe assembly.

FIG. 9 is a view of the glide shoe assembly similar to FIG. 8, with a different hinge arrangement, and different support structure.

FIG. 10 is a view in the manner of FIGS. 8 or 9, showing another construction of the glide shoe assembly, featuring a pair of self-contained glide shoe subassembly units.

FIG. 11 is a view in the manner of FIGS. 8 or 9, showing a construction of the glide shoe assembly with detachable glide shoes.

FIG. 12 is a view in the manner of FIG. 11, showing additional pivotal mounting of the glide shoes.

FIG. 13 is a plan view taken on line l313 in FIG. 12.

FIG. 14 shows a construction similar to FIG. 10, including additional adjustment means.

FIG. 14a is a cross-sectional view taken on line l4a-l4a of FIG. 14.

FIG. 15 is a side view of another form of glide shoe assembly.

FIG. 16 is a perspective view of the glide shoe assembly of FIG. 15, slightly modified.

FIG. 17 is a view of a glide shoe assembly in the manner of FIG. 11, modified.

FIG. 18 is a plan view taken on line 18-18 in FIG. 17.

FIG. 19 is a perspective view of a belt vacuum drum filter equipped with a pair of belt tracking devices of still another construction.

FIG. 20 is a greatly enlarged plan view of the belt tracking device shown in FIG. 19, featuring a pivotally mounted block supporting a rod for combined axial and rotational movements, as well as angular swinging movement. 3

FIG. 20a is a detail view of a substitute member of the block in FIG. 20, allowing for universal self-adj ustment of the rod.

FIG. 21 is a longitudinal part sectional view taken on line 21-21 of the device shown in FIG. 20.

FIG. 22 is a vertical cross-sectional view taken on line 22 22 in FIG. 21.

FIG. 23 is a view of the glide shoe assembly of FIG. 21, modified.

FIG. 24 is a perspective view of another embodiment of the device of FIGS. 20 to 23.

FIG. 25 is an end view of the device taken on line 2525 in FIG. 24.

FIG. 26 is a top view of the device taken on line 26-26 of FIG. 25.

FIG. 27 is a side view of the device taken on line 27-27 of FIG. 26.

FIG. 28 is an enlarged detail view of the self-contained glide shoe subassembly unit of FIG. 14.

FIG. 29 shows a modified form of the glide shoe assembly of FIG. 12, with the glide shoe carried by a T-shaped skeleton.

FIG. 30 is a part-sectional view taken on line 3030 in FIG. 29, showing one form of glide shoe.

FIG. 31 is similar to FIG. 30, showing another form of glide shoe.

FIG. 32 is an exploded view of the glide shoe assemblies shown in FIGS. 30 and 31.

In the perspective view of FIG. 1, the belt tracking and centering devices D-1 and D-2 are mounted opposite each other upon the sides of the frame M of a drum filter unit of generally known construction. The devices D-1 and D2 have gripping and sliding engagement with the respective prepared longitudinal edge portion or guide tracks E1 and E2 of an endless filter belt F. The belt-gripping parts P-l and P-2 of these devices are mounted in support brackets B-1 and B2 respectively, and are biased or resiliently urged in opposite directions, that is transversely of and laterally away from the respective edge portion of the belt, as indicated by respective compression coil springs S-1 and 8-2. The transverse stretch eliminates longitudinal wrinkles from the belt while also centering the same in relation to the filter drum.

The porous filter belt surrounds and frictionally engages the major portion of the circumference of a filter drum 10 mounted for rotation in the direction of arrow A upon a vat V containing a bath of slurry to be filtered. The filter drum with its lower portion immersed in the slurry bath may be of conventional type, that is equipped with conventional filtration panels or filtrate chambers 11 arranged side by side around the periphery of the drum. These filter panels or vacuum chambers are separated from each other by division strips 12 flush with the peripheral edge portions 13 of the filter drum.

The operation of such a vacuum filter drum in a conventional filtration cycle is of itself well known, controlled by the usual trunnion valve here not shown.

The drum being rotated in the direction of arrow A by usual drive mechanism not shown, moves the filter belt through the slurry bath, so it will continuously collect and hold a layer or cake of slurry solids from the bath while filtrate liquid is delivered from the filter panels through and from the interior of the drum. The cake is then continuously removed from the filter belt at a cake discharge station spaced from the drum, in the course of the filtration cycle. A guide roll system for the filter belt comprises guide rolls parallel to the drum axis, mounted in lateral bracket structures 14 and 15 rigidly connected to the slurry tank or vat. In this way the filter belt is guided away from the upper portion of the drum to effect the discharge of the cake material from the belt, and then back onto the lower portion of the drum where the layer of solids is collected from the bath by the vacuum suction of the filter panels.

The guide roll system may comprise three rolls, namely a first or cake discharge roll 16, a second or idler roll 17, and a third or belt tension roll 18. Each end of the tension roll 18 is vertically adjustable for correcting the tension individually for each side edge portion of the filter belt as by means of well known vertical screw spindles indicated at 19.

The belt tracking device in the embodiment of FIGS. 2, 3, 3a, 3b has a belt-gripping part or glide shoe assembly which comprises a pair of opposedly arranged wing members or hinge members 20 and 21 interconnected by a hinge shaft 22. The intermediate portion h-l of this hinge shaft is held in a sleeve 23 rigidly connected to a rod or stem 24 extending at right angles outwardly therefrom. The hinge members are swingable on the end portions h-2 and h-3 of this shaft. The upper hinge member 20 consists of a pair of arms 25 and 26, the inner ends of which are rigidly connected to respective sleeves 20a and 20b having a loose fit on the shaft, and a crossbar 25 rigidly interconnecting the arms. The outer ends of the arms are rigidly connected each to a cylindrical half shell 26 extending parallel to the hinge axis. The half shell has transverse end plates 26a and 26b which hold between them an elongate cylindrical glide shoe member 27 the axis of which is parallel to the hinge axis. For antifriction purposes, an example of a suitable material to constitute these glide shoe memhers is a composition material known as Teflon, to slidingly cooperate with rubber guide tracks on the filter belt. This composition material is otherwise definable as carbon tetrafluoride.

The lower hinge member 21 is substantially similar to the companion member 20, except that the arms 21a and 21b are staggered with respect to the arms of the upper member, in order to accommodate sleeve members 210 and 21d on the hinge shaft 22. The arms 21a and 21b have a crossbar 28 which together with crossbar 25 provides the mounting for a compression spring 29 of adjustable pressure means urging the hinge members towards each other.

The pressure means in this embodiment comprise a bolt 30 extending through the crossbars 25 and 28 and thus transversely of the two hinge members. The threaded end portion 31 of the bolt is surrounded by the compression coil spring 29 confined between the hinge member 20 and a wingnut 33. The head 34 of the bolt and an abutment nut 35 determine the thus adjustable distance d between the glide shoe members 27. Axial screws 35a and 35b hold the glide shoemembers in place and parallel to the hinge axis.

The rod or stem 24 is slidable in a supporting sleeve 36 extending through a vertical bracket plate 37, which sleeve has an external thread so that locknuts 38 and 39 on the thread may hold the sleeve fixed to the bracket plate. .The bracket plate is bolted to a bracket base 39a in such a manner as to be vertically adjustable thereon. The bracket base in turn is bolted to the bracket structure 14 on the vat in such a manner as to be horizontally adjustable thereon due to the provision of slots 3%.

Another compression coil spring C surrounds the threaded end portion 24a of stem 24 as well as the adjoining end portion 360, of the supporting sleeve. This spring is confined between an adjustable abutment as presented by a pair of locknuts 40 on the threaded sleeve end portion 36a, and a wingnut 42 on the threaded end portion 24a of the stem.

The glide shoes 27 of the tensioning devices D-1 and D-2 engage the prepared longitudinal edge portions of the endless filter belt, with springs C of the devices acting in opposite directions so as to apply a transverse unwrinkling stretch to the filter media of the filter belt while also centering the belt relative to the filter drum.

To cooperate with the glide shoes 27 of the tracking devices as illustrated in FIGS. 2, 3, the filter belt is provided with a prepared edge portion comprising a strip element 41 (see FIG. 4) of homogeneous flexible material, for instance rubber or the like. This strip element comprises a flange portion 42 lengthwise secured to the filter media along the length thereof and coplanar therewith. The outer edge of this flange portion is enlarged to form a bead 43 providing a pair of guide tracks 44 and 45 engaged by, and in profile conforming to the glide shoe members 27.

The flange portion 42 is interposed between a pair of strips 46 and 47 of fabric or filter media material which may be secured to the flange portion by sewing. These strips in turn have between them the respective edge of the filter media 48 proper, to which they may be secured by sewing.

The belt-gripping part or glide shoe assembly of the tracking devices in the embodiment of FIG. 3a comprises a pair of parallel hinge shafts and 56 mounted on the respective upper and lower ends of a plate 57 fixed to a stem or rod 58. The intermediate part of each hinge shaft is held in a sleeve member 59 fixed to the plate.

A pair of opposedly arranged hinge members 60 and 61 may be identical each comprising a pair of sleeves 62 and 63 (see FIG. 3b) loosely fitted over the end portions of the respective hinge shafts. A pair of arms 64 and 65 extend rigidly from the respective sleeves, with glide shoes 66 connected to the outer ends of these arms, substantially the same as those shown in the embodiment of FIG. 3. 4

The two hinge members 60 and 61 again are urged towards one another in the manner substantially the same as in FIG. 3.

In the embodiment shown in the perspective view of FIG. 5, a pair of cooperating tracking devices 70 are mounted upon the respective sides or frame portions 71 and 72 of the vat of a belt-type drum filter similar to the one shown in FIG. 1. In this device, the tubular guide for the rod that carries the guide shoe assembly, is mounted for floating movement in a plane transversely of the associated edge portion 70a of the filter belt.

Referring further to FIGS. 6, 7, and 8 showing enlarged details of this device, floating movement of the glide shoe assembly is attained by the provision of a swingable member or plate 73 having one end mounted upon the frame so as to be movable about a pivotal axis A-A (see FIGS. 5 and 6) extending in a direction substantially parallel to the plane of the belt, and substantially at right angles to the edge portion of the belt.

The free end of the swingable plate member 73 has fixed thereto a tubular guide member 75 parallel to pivotal axis A- A. A glide shoe assembly carried by, and movable in this tubular guide may be similar to the one shown in the embodiment of FIGS. 1 to 3. Thus the assembly may comprise a rod 76, a pair of wing members 77 and 78 hinged together by a hinge shaft 78a, and carrying elongate glide shoes 79 and 80 biased towards each other by means bolt 81. A compression coil spring 82 surrounding the outer end portion of the bolt, cooperates with wingnut 83 adjustable for maintaining bias to maintain cooperative sliding engagement between the glide shoes and the beaded edge portion 85 of the belt, while allowing for disengagement should excessive stress develop due to excessive deviation of the belt. Cushioning means or spring means or counterweight means may be provided if desired for balancing the weight of the swingable plate 73 and of the glide shoe assembly carried thereby. The tubular guide member 75 while shown integral with swinging member 73, may be connected to member 73 so as to be detachable as well as adjustable. This may permit the member 73 to be lengthened or shortened, or the tubular guide member to be adjusted in various directions or to be exchanged.

It will be understood, however, that in this tracking device, as well as in any of the other herein illustrated, various other glide shoe assemblies may be employed examples of which are illustrated in FIGS. 9 to 18. For instance in FIG. 9, the wing members 86 and 87 carrying the glide shoes are not symmetrical due to the offset arrangement of the hinge shaft 88. In this way, the transverse shank portion of one wing member 86 is fixed to a rod 89 which in turn operates in the tubular guide member 75. For the purpose of detachably connecting the rod to the shank portion, the rod has a threaded end portion 89a extending through the shank portion, so that a fixed shoulder 89b and a pair of locknuts 896 may be tightened against each other for rigidly connecting the parts to one another. On the other hand, the locknuts may be set in such a manner as to allow for rotation of the glide shoe assembly relative to the rod, for instance where the rod is axially shiftable but not tumable about its axis. In this way also the glide shoe assembly may be fixed at a desired angle relative to the rod. The rod may or may not be tumable about its own axis in a supporting tubular member. While applicable for instance to the device of FIGS. 24 to 27, or to other tracking devices herein illustrated, the glide shoe assembly of FIG. 9 is shown with a different support structure to illustrate other adjustability features. Accordingly, the rod 89 is axially shiftable in a tubular guide member 89d, but may be secured against rotation as by removable screw member 89c engaging key groove 89f in the rod. Removal of screw member 89c allows the rod to rotate in the tubular member. The tubular member in turn may be longitudinally as well as rotationally adjustable in a support structure 89g, as indicated by a setscrew 89h.

The glide shoe assembly in FIG. comprises a rigid U- shaped member 90 having an intermediate body portion 90a and shank portions 90b and 900, the body portion being fixed to a rod 91 in right-angled relationship therewith. Each shank carries a guide shoe embodied in a self-contained subassembly unit 92. This subassembly (see also FIG. 28) comprises a cylindrical housing 93 extending at right angles outwardly from a respective shank of the U-shaped member. The outer end of the housing is closed by a threaded nipple 94, the inner end being closed by threaded nipple 95 formed with a constriction or neck 96 to fit into a cutout 97 at the end of the shank. A stem 98 extending concentric with the housing is guided for axial sliding movement in both said closure nipples. The stem is fixed to a half round shell 99 midway thereof, the shell itself containing a cylindrical glide shoe 100 in the manner shown in FIG. 3. A compression spring 101 surrounds the stem within the housing, and pressing against a collar 102 on the stem maintains the glide shoe in cooperation engagement with the beaded edge portion 103 of the filter belt, in cooperation with the opposedly arranged companion tracking device on shank c. By tightening the closure nipple this subassembly is secured tightly to the U-shaped member. Loosening this nipple then allows the subassembly to be detached by slipping out of the cutout 97 in lateral direction. The embodiment of FIG. 10 may have only one such subassembly unit 92 provided for one of the shanks, while the other shank may have the glide shoe mounted thereon in other ways for example any of those herein shown and described. For convenience, an upper hole 98a in stem 98 may be used pulling the stem upwardly against the spring pressure far enough to expose a lower hole 98b in the stem. Then by placing a pin through this lower hole, the stem with the associated glide shoe may be held in this retracted position.

The glide shoe assembly in FIG. 11 is similar in regard to the double hinged construction to the one shown in FIG. 30, except for the fact that the half round shell 104 with glide shoe is rendered detachable from the associated hinged member 105, so that it may be exchanged, or its effective length be varied.

The glide shoe assembly in FIGS. 12 and 13 comprises wing members 106 and 107 hinged to a rod 107a, but constructed so as to receive a vertical stem 108 in hub 109, allowing for self-adjusting pivotal movement of the glide shoe about the axis of the stem. That is to say, the stem is fixed to shell 110 midway thereof, the shell in turn containing a cylindrical glide shoe 111.

The glide shoe assembly in FIG. 14 is similar in principle to the one of FIG. 10, in regard to the provision of the self-contained glide shoe subassemblies detachably mounted on a rigid U-shaped member. A structural difference lies in the manner in which the rod 112 is adjustably connected to the intermediate body portion of the U-shaped member. As seen in FIG. 14a, the rod has fixed thereto a disc 113 formed with ar cuate slots 114 through which may extend bolts 115 or other suitable elements connecting it to the intermediate body portion of the U-shaped member, the parts being centered relative to each other by an extension 115a of the rod. This connection may be fixed, or it may be loose in the sense that the parts may rotate relative to one another within the limits of the slots. Thus, even if the rod were axially slidable, but not turnable about its axis in the supporting tubular guide member 1120, angular adjustment of the guide shoe assembly about the rod axis is thus available, to conform to the path of the filter belt. In this way, angular adjustment may be provided by setting and fixing the glide shoe assembly at a desired angle to accommodate the path of the filter belt, or to allow the glide shoe assembly to rotationally adjust itself to conform to the path of the filter belt. The extension 1150 may have secured thereon a removable disc or ring member 115b, so that with the bolts 115 removed, the rod and the glide shoe assembly may rotate freely relative to each other. A screw member ll2b or the like engaging a key groove in rod 112 indicates that the rod even though axially shiftable may not be tumable about its own axis. Removal of screw member l12b allows the rod to move rotationally about its own axis. A nut 1120 on the outer threaded end portion of stem 112d serves as a stop that is adjustable so as to avoid excessive frictional pressure of the glide shoe 112e against the bead. 5

In the glide shoe assembly of FIGS. 15 and 16, an elongate base portion 116 is fixed to a rod 117 in right-angled relationship therewith. Glide shoes 118 and 119 are mounted on the free ends of respective opposedly arranged wing portions 120 and 121 consisting of a spring sheet material, and having an intermediate body portion 122 fixed to said base portion 116.

The wing portions may be provided by a length of tube 123 of suitable resiliently yieldable or springy material slitted lengthwise and transversely spread sufficiently to accommodate the glide shoe members 124 and 12S mounted upon the longitudinal edges of the slit, as well as to accommodate the thickness of the beaded edge portion 125a of the filter belt. The slitted tube may be fastened to the base portion 1 16 as by means of a pair of bolts 126 extending through transverse slots 127 provided in the intermediate or body portion of the slitted tube, and allowing for rotational adjustment of the tube.

A pair of bolts 127 and 128 extend transversely through this slitted tube, and with nuts 129 and 130 they provide the means for adjusting the spread or distance between the glide shoe members. In this way, the spread is variable by moving the nuts 129 and 130 upon the threaded bolt either closer together or farther away from each other. The head 131 of the bolt and a wingnut 132 on the free end of the bolt are shown slightly spaced outwardly from the respective wing portions of the slitted tube. The bolts extend through the wing portions with generous tolerance.

The slitted tube in FIGS. and 16 may consist of thin springy sheet material, while the glide shoe members may consist of a material having minimum frictional affinity relative to the rubber tracks on the beaded edge portion of the filter belt. A composition known as Teflon is well suited for that purpose. By reason of the resiliency of the wing portions, the glide shoes will spread apart and release the filter belt when excessive stretching force develops.

Also, the slitted tube member may be of a material of suitable plastic composition integral with or bonded to the glide shoe members which in turn may have minimum frictional affinity relative to the tracks. Also, many cross-sectional shapes other than that of the slitted tube may be employed, and many other variations in the structural combination of the parts that constitute a springy clasp construction or the like designed to cooperate with the tracks on the filter belt.

In the glide shoe assembly in FIGS. 17 and 18, a body portion or plate 133 is fixed to a rod 134 which may be slidable, as well as turnable about its own axis, in the tubular guide member 135. A pair of wing members 136 and 136a of resiliently yieldable sheet material each have a hinge connection with a plate 137 by means of hinge shafts 138 and 139 respectively. The outer ends of the wing members have mounted thereon glide shoes 140 and 141. To this end, a rod 140a parallel to the hinge axis is fixed to the end of the wing member, and a longitudinally slitted glide shoe member or jacket 14% of suitable composition material is fitted over the rod. A pair of bolts 1419 and 141b or threaded rods extend transversely through the wing members, each end of each bolt being adjustably secured to the respective wing members by means of a pair of locknuts 142 and 143 cooperating with spacer nuts 143a and 1440 respectively. Slots 144 in each wing member permit each bolt to be adjusted parallel to itself for varying the resiliency of the wing members. A leaf spring 145 of any suitable strength may be interposed between the outer locknut and the respective wing members for somewhat stiffening the resistance of the resilient wing members, or decrease their resiliency. A slot 146 in this leaf spring may be provided, to allow it to be shifted forward or backward in a manner to vary the resiliency of the wing member. Each wing member may have a cutout 146a. Still another form of the glide shoe assembly may be the one illustrated in FIGS. 13 and 14 of the aforementioned copending application.

The above-mentioned glide shoe assemblies and their modifications may be applied or substituted in any one of the forms of the tracking devices herein shown and described in connection for instance with FIGS. 1, 5, 19, and 24. Another form of tracking device shown in perspective in FIG. 19, embodies the feature of the floating glide shoe assembly, in that the rod carrying the glide shoe assembly is rendered swingable in a plane extending substantially at right angles to the edge portion of the filter belt. Again, as in perspective FIGS. 1 and 5, these tracking devices T-1 and T-2 are mounted upon respective sides or frame structures fixed to the vat structure of the machine.

The tracking device itself in this embodiment (see FIGS. 20 to 23) may comprise a glide shoe assembly similar to the one previously described in FIG. 4. That is to say, a pair of wing members 147 are hinged together through hinge shaft 148, and biased towards each other by spring 149, maintaining glide shoes 150 and 150a in track-engaging relationship with the beaded edge portion 151 of the filter belt. The hinge shaft is connected to the end of a rod 152 in right-angled relationship thereto.

The rod 152 is axially shiftable in a hollow member or block 153, as well as turnable therein about its own axis. The block in turn is contained between, and pivotally mounted in a pair of brackets 154 and 155, to allow for additional swinging movement of the rod. The brackets are so mounted upon the machine that the plane of the swinging movement of the rod will extend substantially in a direction at right angles to the associated edge portion of the filter belt.

Fixed to the brackets is a top plate 156 and a base plate 157. Within this box like structure there are provided a pair of guide members 158 and 159 providing guidance for the swinging movement of the rod. The guide members are detachably connected to the .respective bracket members, which allows for shims to be interposed between the guide members and the brackets, in such a manner that suitable guiding tolerance is provided for the movement of the rod.

The rod together with the glide shoe assembly is biased in an outward axial direction, by means of a compression coil spring 160 surrounding the outer free end portion of the rod. The spring is confined between the block 153 and a wingnut 161 provided upon the outer threaded end of the rod, permitting adjustment of the tension of the spring. In FIG. 200 the pivotally mounted block is replaced by a self-adjusting spherical member 162 confined between bracket members 1621: and 16212.

In FIG. 23 there is shown another glide shoe assembly also applicable to any of the various embodiments or forms of tracking devices herein shown and described. Although embodying a single hinge connection between a pair of wing members carrying glide shoes, this structure differs from the glide shoe assembly in FIG. 21, in that the one wing member 163 is rigidly connected to rod 164 due to the offset disposition of the hinge connection 165. This structure allows the rod 164 to be simply welded or otherwise fixed directly to the shank portion 166 of wing member 163, thus simplifying the construction of the hinge connection upon which the movement of the other wing member 163a depends. This glide shoe assembly also may be substituted for instance in any one of the tracking devices shown in FIGS. 1, 5, 19, and 24.

The tracking device shown in the perspective of FIG. 24 is similar in principle to the one of FIG. 19 above described, in that it is shown to have a glide shoe assembly carried by a rod mounted for swinging movement in a plane substantially at right angles to the associated edge portion of the filter belt.

Referring further to FIGS. 25, 26, 27, the glide shoe assembly 167 is hinge-connected to a rod 168, with the hinge axis in right-angled relationship to the axis of the rod. This rod is axially shiftable as well as turnable about its own axis in a block 169 which is mounted for rotation on a bracket struc ture 170 so constructed and arranged as to allow for swinging movement of the rod in a plane substantially at right angles to the associated edge portion of the filter belt.

Accordingly with the belt moving in the direction of arrow A-l (see FIG. 25), the bracket structure has a bracket plate 171 extending rigidly at an angle B from a horizontal base plate 172 mounted on the sideframe of the machine. The angle B is such that the plane of the bracket plate as well as the plane of swinging movement of the rod extend substantially at right angles to the associated edge portion of the filter belt. The bracket structure is mounted on the side frame by means of bolts 173 extending through slots 174, allowing the bracket structure to be shifted horizontally (see Arrow A-2) to bring the glide shoe assembly into substantial alignment with the associated edge portion of the filter belt.

From FIG. 26 it may be seen that the block 169 may be held and secured in the bracket plate by means of a retainer ring 175 engaging a reduced cylindrical portion 176 of the block. With the belt moving in the direction of arrow A-3, guidance for the swinging movement of the rod is provided by a guide contact member 177 detachably fixed to the bracket plate. Again, as in the preceding embodiments, a compression coil spring 178 surrounds the outer end portion of the rod, so as to be confined between the block and a wingnut 179 which may be manipulated to adjust the spring tension and thus the axial pull upon the rod.

A glide shoe assembly in FIG. 30 is similar to the one in FIG. 12, in that it provides for the additional pivotal movement of glide shoe members about an axis extending perpendicular to the axis of the glide shoes midway between the ends thereof.

In this embodiment (see also FIGS. 30, 31, 32) the glide shoe is built around a T-shaped skeleton 180 comprising a horizontal rod 181 and a vertical stem 182 extending at right angles from the rod midway between the ends thereof and fitted into hub 182a of wing member 182b in embodiment of FIG. 29.

A jacket 181a of suitable antifrictional composition material may be applied to the horizontal rod 181 to enclose the same and to provide cylindrical glide shoe surfaces for the tracks on the filter belt. For example, in FIG. 30 a single jacket 183 surrounds the rod. In FIG. 31 two cylindrical glide shoe members 184 and 185 are slipped over the rod from the respective ends thereof, as may also be seen from the exploded view in FIG. 32. Such two glide shoe members may be spaced from one another at their inner ends (see FIG. 31), or they may have the endwise abutting relationship of glide shoe members 186 and 187 in FIG. 32, each of which has a recess 188 accommodating the stem 182. The glide shoe members are thus readily removable and exchangeable, and their effective length may thus be varied.

Referring once more to FIG. 9, this embodiment is capable of various alternatives in a number of combinations and variations. For instance, the head portion or glide shoe assembly may be fixed to rod 89, or it may be tumable relative to the rod. The rod itself may be tumable as well as axially shiftable in tubular guide member 89d, or it may be axially shiftable while secured against rotation, depending upon whether or not the screw member 89e functioning as a key is in place. If a set screw be provided instead of screw member 89e, it can fix the rod relative to the tubular member 89d in any rotational or axially shifted position relative to the tubular member. The tubular member in turn by means of setscrew 89h may be fixed in any rotational or axial position relative to support structure 89g. The glide shoe assembly of FIG. 9 may be substituted in other tracking devices herein illustrated, or other glide shoe assemblies herein shown may replace the one in FIG. 9.

We claim:

1. In a rotary drum filter apparatus of the endless travelling filter-belt type, the filter belt having beaded edge portions connected to a web of filter material, the bead of each edge portion providing track faces opposite each other and ad jacent to the juncture of the bead with the web,

a tensioning device which comprises a glide shoe assembly having a pair of elongate parallel glide shoes opposite each other, each to engage a length of a respective track, said glide shoe assembly being constructed and arranged to urge said glide shoes towards each other, and for maintaining them in cooperative engagement with the tracks,

a rod extending from said glide shoe assembly in right angle relationship to said glide shoes, and laterally away from the associated edge portion of the filter belt,

a guide member wherein said rod is axially shiftable,

bias means for urging said rod in axial direction away from said belt,

support structure for said guide member, constructed and arranged to floatingly support said glide shoe assembly for bodily up-and-down movement, in a plane extending substantially at right angles to the adjacent edge portion of the belt, while maintaining said glide shoes in cooperative engagement with said tracks.

2. The device according to claim 1, wherein said rod is turnable in said guide member about its own axis.

3. The device according to claim 1, wherein said glide shoe assembly has a pair of wing members having a hinge connection with one another at their inner ends, and the glide shoes connected to their outer ends, and wherein the rod extends from one of said wing members and in right-angled relationship to the hinge axis.

4. The device according to claim 1, wherein said glide shoe assembly comprises a pair of wing members having a pair of elongate glide shoes connected to the respective outer ends thereof, a plate extending between the inner ends of said wing members transversely thereof, and substantially parallel to said glide shoes, and connected to said rod and a hinge connection between each wing member and the respective adjacent portion of said plate, with the hinge axis substantially parallel to said glide shoes.

5. The device according to claim 1, wherein the glide shoe assembly has a pair of wing members and a pair of elongate glide shoes each having a holder connected to the respective outer end of said wing members, hinge means interconnecting the inner ends of said wing members, with the hinge axis substantially parallel to the glide shoes, and means for detachably connecting said glide shoe holders to respective wing members.

6. The device according to claim 1, wherein said glide shoe assembly comprises a pair of wing members, hinge means interconnecting the inner ends of said wing members, and wherein at least one of the glide shoes carried by the wing members has mounting means providing for pivotal movement of the glide shoe about an axis perpendicular to the axis of the shoe.

7. The device according to claim 1, wherein said glide shoe assembly has a U-shaped member including an intermediate body portion and a pair of shank portions, a glide shoe subassembly unit having a cylindrical housing mounted to extend at right angles outwardly from the free end of one shank, and having a closure at each end, a stem extending axially through said housing and through said closures and axially movable therein, an elongate glide shoe connected to the inner end of said stem, midway between the ends of said shoe, and spring means provided in said housing, effective to urge said stem and glide shoe into cooperative engagement with said head.

8. The device according to claim 1, wherein said glide shoe assembly comprises a pair of resiliently deflectable wing members interconnected at their inner ends, and with the glide shoes connected to their outer ends, and adjusting means cooperative with said wing members for maintaining the glide shoes spaced from one another, said wing members being defiectably yieldable to release the associated bead in case of excessive deviation of the filter belt.

9. In a rotary drum filter apparatus of the endless travelling filter-belt type, the filter belt having beaded edge portions connected to a web of filter material, the bead of each edge portion providing track faces opposite each other and adjacent to the juncture of the bead with the web,

a tensioning device which comprises a glide shoe assembly having a pair of elongate parallel glide shoes opposite each other, each to engage a length of a respective track, said glide shoe assembly being constructed and arranged to urge said glide shoes towards each other, and for maintaining them in cooperative engagement with the tracks,

a rod extending from said glide shoe assembly in right-angled relationship to said glide shoes, and laterally away from the associated edge portion of the filter belt,

a tubular member wherein said rod is axially shiftable,

bias means for urging said rod in axial direction away from said belt,

support structure for said tubular member, which comprises a swingable member mounted for swinging movement in a plane parallel to the adjacent edge portion of the belt, as well as perpendicular to the plane of the associated portion of the filter belt, said tubular member being fixed to the free end of said swingable member so as to extend parallel to the pivotal axis of said swinging member,

10. The device according to claim 9, wherein said rod is tumable about its own axis in said tubular member.

11. The device according to claim 9, wherein said glide shoe assembly is rotationally adjustable relative said rod.

12. The device according to claim 9, wherein said glide shoe assembly is rotationally adjustable relative to said rod, said rod being secured against rotation about its own axis.

13. In a rotary drum filter apparatus of the endless travelling filter-belt type, the filter belt having beaded edge portions connected to a web of filter material, said edge portions providing track faces opposite each other and adjacent to the juncture of the head with the web,

a tensioning device which comprises a glide shoe assembly having a pair of elongate parallel glide shoes opposite each other, each to engage a length of a respective track,

said glide shoe assembly being constructed and arranged to urge said glide shoes towards each other, and for maintaining them in cooperative engagement with the tracks,

a rod extending from said glide shoe assembly in right angle relationship to said glide shoes, and laterally away from the associated edge portion of the filter belt,

support structure for said rod, which comprises a hollow member slidable as well as tumable on said rod,

and bracket means supporting said hollow member, said bracket means and hollow member being constructed and arranged relative to each other to allow for swinging movement of said rod in a plane extending substantially at right angles to the associated edge portion of the filter belt,

and bias means for urging said rod in axial direction away from the associated edge portion of the filter belt.

14. The device according to claim 13, wherein said hollow member is in the form of a block having a pair of trunnions tumable about an axis extending perpendicular to the plane of said swinging movement of the rod, and a pair of bracket members are provided in fixed relationship to each other, and constructed and arranged for operatively supporting between them said block, said bracket members having bearing means for the respective trunnion of said block.

15. The device according to claim 13, wherein said hollow member is in the form of a spherical member mounted in said bracket members for self-adjustability.

16. The device according to claim 13, wherein said hollow member is in the form of a block having a pivot extending therefrom perpendicular to the plane of said swinging movement of the rod, and wherein a bracket member is provided, constructed and arranged for operatively supporting said block, said bracket member having bearing means for the pivot of said block.

17. in a rotary drum filter apparatus of the endless travelling filter-belt type, the filter belt having beaded edge portions connected to a web of filter material, the bead of each edge portion providing faces opposite each other and adjacent to the juncture of the head with the web,

a tensioning device which comprises a pair of wing members having a single hinge connection with one another at their inner ends, a pair of elongate glide shoes, engaging said tracks, means connecting said glide shoes to the respective outer ends of said wing members so that the glide shoes extend substantially parallel to one another and substantially parallel to the hinge axis,

a rod extending rigidly from one of said wing members and in right-angled relationship to the hinge axis, and laterally away from the associated edge portion of the filter belt,

first bias means effective between said wing members urging said glide shoes towards each other and maintaining them cooperatively engaged with said tracks, but adapted to release the associated bead as a result of excessive strain occurring laterally outwardly in the direction of said rod,

support structure for said rod, wherein said rod is movable along its longitudinal axis together with said wing members and glide shoes, as well as movable rotationally about said axis,

and second bias means effective to urge said rod in the longitudinal direction thereof away from the filter belt.

18. in a rotary drum filter apparatus of the endless travelling filter-belt type, the filter belt having beaded edge portions connected to a web of filter material, the bead of each edge portion providing track faces opposite each other and adjacent to the juncture of the bead with the web,

a tensioning device which comprises a pair of elongate glide shoes of cylindrical shape opposite each other, and consisting of a material having antifriction and antifouling characteristics relative to said head, each glide shoe to engage a length of a respective track, a pair of opposedly arranged wing members, means for mounting said glide shoes upon the respective outer ends of said wing members, which means comprise a holder for each said glide shoe, connected to a respective wing member, means interconnecting the inner ends of said wing members, the assembly of said glide shoes, said holders, and said interconnected wing members being constructed and arranged to urge said glide shoes towards each other for maintaining them in cooperative engagement with said tracks, but adapted to release the associated bead in care of excessive strain occurring in a direction laterally outwardly away from the associated bead,

a rod extending from the outer end of said assembly in rightangled relationship to said glide shoes and laterally away from the associated bead, support structure for said rod, wherein said rod is movable along its longitudinal axis together with said assembly, and bias means effective to urge said rod in the longitudinal direction thereof away from said filter belt.

19. The device according to claim 18, wherein said glide shoes are rotationally adjustable about their respective axes in said holders. 7

20. The device according to claim 18, wherein said glide shoe assembly comprises a pair of wing members, wherein a hinge connection is provided between said wing members, wherein said holder has a pivotal connection with the respective wing member, disposed substantially midway between the ends of said glide shoe, and wherein bias means are provided effective between said wing members urging said glide shoes towards each other and maintaining them cooperatively engaged with the tracks.

21. In a rotary drum filter apparatus of the endless travelling filter-belt type, the filter belt having beaded edge portions connected to a web of filter material, the bead of each edge portion providing track faces opposite each other and adjacent to the juncture of the bead with the web,

a tensioning device which comprises a glide shoe assembly having a pair of wing members, a pair of cylindrical elongate glide shoes consisting of a composition material having antifriction and antifouling characteristics relative to the surface of said bead, means for mounting said glide shoes upon the outer ends of said wings, a plate extending between the inner ends of said wing members transversely thereof, and substantially parallel to said glide shoes, and.

a hinge connection between each wing member and the respective adjacent portion of said plate, with the hinge axis substantially parallel to said glide shoes,

pressure means urging said glide shoes towards each other, and maintaining them in cooperative relationship with respective tracks, but adapted to release the bead as a result of excessive strain occurring in a direction laterally outwardly away from the associated bead,

a rod extending outwardly from said plate in right-angled relationship with said hinge axes,

connected to a web of filter material, the bead of each edge 1 portion providing track faces opposite each other and adjacent to the juncture of the bead with the web,

a tensioning device which comprises a pair of wing members, hinge means interconnecting the'inner ends of said wing members, elongate glide shoes carried by said wing members, said glide shoes having mounting means providing for pivotal movement of the glide shoes about an axis perpendicular to the axis of the shoe,

pressure means for urging said glide shoes towards each other, and maintaining them in cooperative relationship with respective tracks, but adapted to release the bead in case of excessive strain occurring in a direction laterally outwardly away from the associated bead,

a rod extending outwardly from said glide shoe assembly in right-angled relationship with said hinge means,

support structure for said rod, wherein said rod is movable along its longitudinal axis together with said glide shoe assembly,

and bias means effective to urge said rod in the axial direction thereof.

24. The device according to claim 23, wherein said glide shoe is of cylindrical shape, and wherein said mounting means.

comprise an elongate shell accommodating said cylindrical shape, said glide member being endwise supported in said shell, and a stem extending at right angles from said shell, and a hub portion on the associated wing member, surrounding and guiding said stem.

25. The device according to claim 23, wherein said glide shoes are of cylindrical shape, and wherein said mounting means for the pivotal movement is in the form of a T-shaped skeleton comprising a horizontal rod and a stem extending perpendicular from said rod midway between the ends thereof, and a hub portion on the associated wing member, surrounding said stern, and wherein a cylindrical jacket of glide shoe material surrounds said rod, said material being a composition having antifriction and antifouling characteristics relative to said bead.

26. In a rotary drum filter apparatus of the endless travelling filter-belt type, the filter belt having beaded edge portions connected to a web of filter material, the bead of each edge portion providing track faces opposite each other and adjacent to the juncture of the bead with the web,

a tensioning device which comprises a Ushaped member having an intermediate body portion and 'a pair of shank portions extending rigidly therefrom, a pair of elongate glide shoes adapted to engage respective track faces opposite each other, means for pivotally mounting said glide shoes upon the outer end of the respective shank portions, said mounting means comprising a stern extending perpendicular to the glide shoe halfway between the ends thereof, and guide means provided on each said shank portion for the respective stems, and bias means effective in the axial direction of at least one of said stem, for urging the glide shoes towards each other and maintaining them in cooperative relationship with said tracks, but adapted to release the associated bead in case of excessive strain imposed upon the glide shoes in the direction outwardly away from said bead,

a rod extending outwardly from said intermediate body portion of the U-shaped member in right-angled relationship with said body portion, and laterally away from said bead,

support means for said rod, wherein said rod is movable along its longitudinal axis together with said glide shoe assembly,

and bias means effective to urge said rod in the axial direction thereof away from said filter belt.

27. The device according to claim 26, with the addition of means for detachably connecting said body portion to said 5 rod, so that said body portion is turnable about said rod.

28. In a rotary drum filter apparatus of the endless travelling filter-belt type, the filter belt having beaded edge portions connected to a web of filter material, the bead of each edge portion providing track faces opposite each other and adjacent to the juncture of the bead with the web,

a tensioning device which comprises a pair of wing members opposite each other, a pair of elongate glide shoes adapted to engage said track faces opposite each other, said guide shoes consisting of a material having antifriction and antifouling characteristics relative to said bead, means for mounting said glide shoes on the outer ends of respective wing members, a rod extending in a direction substantially in the plane of the web, and laterally away from said wing members and from said glide shoes, means interconnecting the inner ends of said wing members and the adjacent end of said rod so that the rod lies in a plane intersecting substantially at right angles with said filter web and with said glide shoes, the assembly of said wing member, said glide shoes, and said rod being constructed and arranged to urge said glide shoes towards each other for maintaining them in cooperative engagement with said tracks, but adapted to release the bead in case of excessive strain occurring laterally outwardly in the direction of said rod,

support structure for said rod, which comprises a tubular guide member wherein said rod together with said wing members and glide shoes is shiftable in axial direction, and the glide shoe assembly is turnable about the axis of 3 5 the rod and bias means for urging said rod in axial direction away from said filter belt.

29. In a rotary drum filter apparatus of the endless travelling filter-belt type, said filter belt having beaded edge portion connected to a web of filter material, the bead of each edge portion providing track faces opposite each other and adjacent to thejuncture of the bead with the web,

a tensioning device which comprises a pair of elongate glide shoes of cylindrical shape adapted to engage said tracks opposite to each other, said glide shoes consisting of a composition material having antifrictional and antifouling characteristics relative to the surface of said bead, a pair of opposedly arranged wing members,

respective wing members,

hinge means providing a connection between the inner ends of said wing members, to allow for swinging of each wing member about an individual axis substantially parallel to said glide shoes,

pressure means for urging said wing members towards each other and maintaining them in cooperative engagement with said tracks, but adapted to release the bead in case of excessive transverse strain by the glide shoes upon said bead in a direction laterally outwardly therefrom,

a rod extending from said hinge connection in rectangular relationship to axis of said hinge connection, and laterally away from the associated edge portion of the filter belt,

from the filter belt,

and bias means by urging said rod in axial direction away from said filter belt.

30. In a rotary drum filter apparatus the device according to claim 29, wherein said hinge means have a single hinge axis.

means for mounting said glide shoes upon the outer ends of 31. In a rotary drum filter apparatus of the endless travelling filter-belt type, the filter belt having beaded edge portions connected to a web of filter material, the bead of each edge portion providing track faces opposite each other and adjacent to the juncture of the bead with the web,

a tensioning device which comprise a glide shoe assembly having an intermediate body portion, a pair of wing members extending from said body portion opposite each other, and consisting of a resiliently deflectable material, a pair of elongate glide shoes connected to the outer ends of said wing members, normally tensioned to engage respective tracks, but allowing said glide shoes to release said beaded edge portions due to resilient deflection and yielding of said wing members in case of excessive transverse strain upon said glide shoes,

a rod extending from said body portion in rectangular relationship to said glide shoes, and laterally away from said filter belt,

support means for said rod, which comprise a tubular guide member wherein said rod is shiftable in axial direction, and support structure for said tubular member, constructed and arranged for maintaining said tubular member, said rod and said glide shoes in cooperative relationship with the associated edge portion of the filter belt, while allowing said rod to shift towards and away from the filter belt.

32. The device according to claim 31, wherein there are provided means for adjusting the degree of yieldability of said wing members.

33. The device according to claim 31, wherein said wing members each have a hinge connection with said intermediate body.

34. In a rotary drum filter apparatus of the endless travelling filter-belt type, the filter belt having beaded edge portions connected to a web of filter material, the bead of each edge portion providing track faces opposite each other and adjacent to the juncture of the bead with the web,

a tensioning device which comprises an assembly of a pair of opposedly arranged elongate glide shoes adapted to engage respective track faces of said bead opposite each other, said assembly being constructed and arranged to urge said glide shoes towards each other and maintaining them in cooperative engagement with the tracks, but adapted to release the bead in case of excessive strain occurring in a direction laterally outwardly away from the associated bead, and in the plane of the filter belt,

a rod extending from said glide shoe assembly laterally away from the associated edge portion of the filter belt and in the plane of said belt said rod having an outer threaded end portion,

a horizontal externally threaded tubular guide member wherein said rod is shiftable in axial direction, said tubular member having external thread,

a support bracket structure comprising an upright portion through which said threaded tubular member extends,

a pair of locknuts provided on said threaded tubular member, one on each side of said upright bracket portion for fixing said tubular member in said bracket portion in horizontally adjusted position,

adjustable locking means on the outer end portion of said threaded tubular member and providing a stop means adjustable on said tubular member,

a stop nut provided on said outer threaded end of said rod,

and a compression coil spring surrounding the outer end portion of said tubular member and said rod, confined between said stop means and said stop nut.

35. In a rotary drum filter apparatus of the endless travelling filter-belt type, the filter belt having beaded edge portion connected to a web of filter material, the bead of each edge portion providing track faces opposite each other and adjacent to the juncture of the bead with the web, a tensioning device which comprises l a pair of elongate parallel glide shoes adapted to engage said tracks opposite each other, a shell of resiliently deflectable material having substantially C-shaped cross-sectional configuration with the glide shoes mounted upon the ends thereof parallel to the longitudinal axis of said shell, said glide shoes being biased towards each other by the resiliency of the wing portions of said shell, but effective to release the bead in case of excessive transverse strain upon said glide shoes,

a rod extending from the intermediate body portion of said shell, and in rectangular relationship with the axis of shell and said glide shoes, and in a direction outwardly away from said body portion, and laterally away from the associated edge portion of the filter belt,

support means for said rod, which comprise a tubular guide member wherein said rod is shiftable in axial direction, a support structure for said tubular member;

and bias means for urging said rod in axial direction away from said filter belt.

36. The device according to claim 35, wherein there are provided means effective between the wing portions of said shell, and operable for adjusting a gap between said glide shoes, and thereby adjusting the pressure of said glide shoes upon said tracks.

37. The device according to claim 35, wherein a transverse tie member extends through the wing portions of said shell with adjustable means provided on said tie member for limiting the movement of said wing members.

38. The device according to claim 35, wherein said rod is formed with an enlarged end portion conforming to the external contour of the intermediate body portion of the shell, said enlarged end portion being connected to said shell.

39. The device according to claim 35, wherein said rod is formed with an enlarged end portion adapted to the contour of the intermediate body portion of said shell, and wherein fastening means are provided for detachably connecting said body portion of the shell to said enlarged end portion of the rod. 1 

1. In a rotary drum filter apparatus of the endless travelling filter-belt type, the filter belt having beaded edge portions connected to a web of filter material, the bead of each edge portion providing track faces opposite each other and adjacent to the juncture of the bead with the web, a tensioning device which comprises a glide shoe assembly having a pair of elongate parallel glide shoes opposite each other, each to engage a length of a respective track, said glide shoe assembly being constructed and arranged to urge said glide shoes towards each other, and for maintaining them in cooperative engagement with the tracks, a rod extending from said glide shoe assembly in right angle relationship to said glide shoes, and laterally away from the associated edge portion of the filter belt, a guide member wherein said rod is axially shiftable, bias means for urging said rod in axial direction away from said belt, support structure for said guide member, constructed and arranged to floatingly support said glide shoe assembly for bodily up-and-down movement, in a plane extending substantially at right angles to the adjacent edge portion of the belt, while maintaining said glide shoes in cooperative engagement with said tracks.
 2. The device according to claim 1, wherein said rod is turnable in said guide member about its own axis.
 3. The device according to claim 1, wherein said glide shoe assembly has a pair of wing members having a hinge connection with one another at their inner ends, and the glide shoes connected To their outer ends, and wherein the rod extends from one of said wing members and in right-angled relationship to the hinge axis.
 4. The device according to claim 1, wherein said glide shoe assembly comprises a pair of wing members having a pair of elongate glide shoes connected to the respective outer ends thereof, a plate extending between the inner ends of said wing members transversely thereof, and substantially parallel to said glide shoes, and connected to said rod and a hinge connection between each wing member and the respective adjacent portion of said plate, with the hinge axis substantially parallel to said glide shoes.
 5. The device according to claim 1, wherein the glide shoe assembly has a pair of wing members and a pair of elongate glide shoes each having a holder connected to the respective outer end of said wing members, hinge means interconnecting the inner ends of said wing members, with the hinge axis substantially parallel to the glide shoes, and means for detachably connecting said glide shoe holders to respective wing members.
 6. The device according to claim 1, wherein said glide shoe assembly comprises a pair of wing members, hinge means interconnecting the inner ends of said wing members, and wherein at least one of the glide shoes carried by the wing members has mounting means providing for pivotal movement of the glide shoe about an axis perpendicular to the axis of the shoe.
 7. The device according to claim 1, wherein said glide shoe assembly has a U-shaped member including an intermediate body portion and a pair of shank portions, a glide shoe subassembly unit having a cylindrical housing mounted to extend at right angles outwardly from the free end of one shank, and having a closure at each end, a stem extending axially through said housing and through said closures and axially movable therein, an elongate glide shoe connected to the inner end of said stem, midway between the ends of said shoe, and spring means provided in said housing, effective to urge said stem and glide shoe into cooperative engagement with said bead.
 8. The device according to claim 1, wherein said glide shoe assembly comprises a pair of resiliently deflectable wing members interconnected at their inner ends, and with the glide shoes connected to their outer ends, and adjusting means cooperative with said wing members for maintaining the glide shoes spaced from one another, said wing members being deflectably yieldable to release the associated bead in case of excessive deviation of the filter belt.
 9. In a rotary drum filter apparatus of the endless travelling filter-belt type, the filter belt having beaded edge portions connected to a web of filter material, the bead of each edge portion providing track faces opposite each other and adjacent to the juncture of the bead with the web, a tensioning device which comprises a glide shoe assembly having a pair of elongate parallel glide shoes opposite each other, each to engage a length of a respective track, said glide shoe assembly being constructed and arranged to urge said glide shoes towards each other, and for maintaining them in cooperative engagement with the tracks, a rod extending from said glide shoe assembly in right-angled relationship to said glide shoes, and laterally away from the associated edge portion of the filter belt, a tubular member wherein said rod is axially shiftable, bias means for urging said rod in axial direction away from said belt, support structure for said tubular member, which comprises a swingable member mounted for swinging movement in a plane parallel to the adjacent edge portion of the belt, as well as perpendicular to the plane of the associated portion of the filter belt, said tubular member being fixed to the free end of said swingable member so as to extend parallel to the pivotal axis of said swinging member.
 10. The device according to claim 9, wherein said rod is turnable about its own axis in said tubular member.
 11. The device aCcording to claim 9, wherein said glide shoe assembly is rotationally adjustable relative said rod.
 12. The device according to claim 9, wherein said glide shoe assembly is rotationally adjustable relative to said rod, said rod being secured against rotation about its own axis.
 13. In a rotary drum filter apparatus of the endless travelling filter-belt type, the filter belt having beaded edge portions connected to a web of filter material, said edge portions providing track faces opposite each other and adjacent to the juncture of the bead with the web, a tensioning device which comprises a glide shoe assembly having a pair of elongate parallel glide shoes opposite each other, each to engage a length of a respective track, said glide shoe assembly being constructed and arranged to urge said glide shoes towards each other, and for maintaining them in cooperative engagement with the tracks, a rod extending from said glide shoe assembly in right angle relationship to said glide shoes, and laterally away from the associated edge portion of the filter belt, support structure for said rod, which comprises a hollow member slidable as well as turnable on said rod, and bracket means supporting said hollow member, said bracket means and hollow member being constructed and arranged relative to each other to allow for swinging movement of said rod in a plane extending substantially at right angles to the associated edge portion of the filter belt, and bias means for urging said rod in axial direction away from the associated edge portion of the filter belt.
 14. The device according to claim 13, wherein said hollow member is in the form of a block having a pair of trunnions turnable about an axis extending perpendicular to the plane of said swinging movement of the rod, and a pair of bracket members are provided in fixed relationship to each other, and constructed and arranged for operatively supporting between them said block, said bracket members having bearing means for the respective trunnion of said block.
 15. The device according to claim 13, wherein said hollow member is in the form of a spherical member mounted in said bracket members for self-adjustability.
 16. The device according to claim 13, wherein said hollow member is in the form of a block having a pivot extending therefrom perpendicular to the plane of said swinging movement of the rod, and wherein a bracket member is provided, constructed and arranged for operatively supporting said block, said bracket member having bearing means for the pivot of said block.
 17. In a rotary drum filter apparatus of the endless travelling filter-belt type, the filter belt having beaded edge portions connected to a web of filter material, the bead of each edge portion providing faces opposite each other and adjacent to the juncture of the bead with the web, a tensioning device which comprises a pair of wing members having a single hinge connection with one another at their inner ends, a pair of elongate glide shoes, engaging said tracks, means connecting said glide shoes to the respective outer ends of said wing members so that the glide shoes extend substantially parallel to one another and substantially parallel to the hinge axis, a rod extending rigidly from one of said wing members and in right-angled relationship to the hinge axis, and laterally away from the associated edge portion of the filter belt, first bias means effective between said wing members urging said glide shoes towards each other and maintaining them cooperatively engaged with said tracks, but adapted to release the associated bead as a result of excessive strain occurring laterally outwardly in the direction of said rod, support structure for said rod, wherein said rod is movable along its longitudinal axis together with said wing members and glide shoes, as well as movable rotationally about said axis, and second bias means effective to urge said rod in the longitudinal direction thereof awaY from the filter belt.
 18. In a rotary drum filter apparatus of the endless travelling filter-belt type, the filter belt having beaded edge portions connected to a web of filter material, the bead of each edge portion providing track faces opposite each other and adjacent to the juncture of the bead with the web, a tensioning device which comprises a pair of elongate glide shoes of cylindrical shape opposite each other, and consisting of a material having antifriction and antifouling characteristics relative to said bead, each glide shoe to engage a length of a respective track, a pair of opposedly arranged wing members, means for mounting said glide shoes upon the respective outer ends of said wing members, which means comprise a holder for each said glide shoe, connected to a respective wing member, means interconnecting the inner ends of said wing members, the assembly of said glide shoes, said holders, and said interconnected wing members being constructed and arranged to urge said glide shoes towards each other for maintaining them in cooperative engagement with said tracks, but adapted to release the associated bead in care of excessive strain occurring in a direction laterally outwardly away from the associated bead, a rod extending from the outer end of said assembly in right-angled relationship to said glide shoes and laterally away from the associated bead, support structure for said rod, wherein said rod is movable along its longitudinal axis together with said assembly, and bias means effective to urge said rod in the longitudinal direction thereof away from said filter belt.
 19. The device according to claim 18, wherein said glide shoes are rotationally adjustable about their respective axes in said holders.
 20. The device according to claim 18, wherein said glide shoe assembly comprises a pair of wing members, wherein a hinge connection is provided between said wing members, wherein said holder has a pivotal connection with the respective wing member, disposed substantially midway between the ends of said glide shoe, and wherein bias means are provided effective between said wing members urging said glide shoes towards each other and maintaining them cooperatively engaged with the tracks.
 21. In a rotary drum filter apparatus of the endless travelling filter-belt type, the filter belt having beaded edge portions connected to a web of filter material, the bead of each edge portion providing track faces opposite each other and adjacent to the juncture of the bead with the web, a tensioning device which comprises a glide shoe assembly having a pair of wing members, a pair of cylindrical elongate glide shoes consisting of a composition material having antifriction and antifouling characteristics relative to the surface of said bead, means for mounting said glide shoes upon the outer ends of said wings, a plate extending between the inner ends of said wing members transversely thereof, and substantially parallel to said glide shoes, and a hinge connection between each wing member and the respective adjacent portion of said plate, with the hinge axis substantially parallel to said glide shoes, pressure means urging said glide shoes towards each other, and maintaining them in cooperative relationship with respective tracks, but adapted to release the bead as a result of excessive strain occurring in a direction laterally outwardly away from the associated bead, a rod extending outwardly from said plate in right-angled relationship with said hinge axes, support structure for said rod, wherein said rod is movable along its longitudinal axis together with said glide shoe assembly, and bias means effective to urge said rod in the axial direction thereof away from said filter belt.
 22. The device according to claim 21, wherein said rod is fixedly connected to said plate, and is rotationally movable in said support structure.
 23. In a rotary drum filter apparatus of the endless travelling filter-belt type, the filter belt having beaded edge portions connected to a web of filter material, the bead of each edge portion providing track faces opposite each other and adjacent to the juncture of the bead with the web, a tensioning device which comprises a pair of wing members, hinge means interconnecting the inner ends of said wing members, elongate glide shoes carried by said wing members, said glide shoes having mounting means providing for pivotal movement of the glide shoes about an axis perpendicular to the axis of the shoe, pressure means for urging said glide shoes towards each other, and maintaining them in cooperative relationship with respective tracks, but adapted to release the bead in case of excessive strain occurring in a direction laterally outwardly away from the associated bead, a rod extending outwardly from said glide shoe assembly in right-angled relationship with said hinge means, support structure for said rod, wherein said rod is movable along its longitudinal axis together with said glide shoe assembly, and bias means effective to urge said rod in the axial direction thereof.
 24. The device according to claim 23, wherein said glide shoe is of cylindrical shape, and wherein said mounting means comprise an elongate shell accommodating said cylindrical shape, said glide member being endwise supported in said shell, and a stem extending at right angles from said shell, and a hub portion on the associated wing member, surrounding and guiding said stem.
 25. The device according to claim 23, wherein said glide shoes are of cylindrical shape, and wherein said mounting means for the pivotal movement is in the form of a T-shaped skeleton comprising a horizontal rod and a stem extending perpendicular from said rod midway between the ends thereof, and a hub portion on the associated wing member, surrounding said stem, and wherein a cylindrical jacket of glide shoe material surrounds said rod, said material being a composition having antifriction and antifouling characteristics relative to said bead.
 26. In a rotary drum filter apparatus of the endless travelling filter-belt type, the filter belt having beaded edge portions connected to a web of filter material, the bead of each edge portion providing track faces opposite each other and adjacent to the juncture of the bead with the web, a tensioning device which comprises a U-shaped member having an intermediate body portion and a pair of shank portions extending rigidly therefrom, a pair of elongate glide shoes adapted to engage respective track faces opposite each other, means for pivotally mounting said glide shoes upon the outer end of the respective shank portions, said mounting means comprising a stem extending perpendicular to the glide shoe halfway between the ends thereof, and guide means provided on each said shank portion for the respective stems, and bias means effective in the axial direction of at least one of said stem, for urging the glide shoes towards each other and maintaining them in cooperative relationship with said tracks, but adapted to release the associated bead in case of excessive strain imposed upon the glide shoes in the direction outwardly away from said bead, a rod extending outwardly from said intermediate body portion of the U-shaped member in right-angled relationship with said body portion, and laterally away from said bead, support means for said rod, wherein said rod is movable along its longitudinal axis together with said glide shoe assembly, and bias means effective to urge said rod in the axial direction thereof away from said filter belt.
 27. The device according to claim 26, with the addition of means for detachably connecting said body portion to said rod, so that said body portion is turnable about said rod.
 28. In a rotary drum filter apparatus of the endless travelling filter-belt type, the filter belt having beaded edge portions connected to a web of filter material, the bead of each edge portion prOviding track faces opposite each other and adjacent to the juncture of the bead with the web, a tensioning device which comprises a pair of wing members opposite each other, a pair of elongate glide shoes adapted to engage said track faces opposite each other, said guide shoes consisting of a material having antifriction and antifouling characteristics relative to said bead, means for mounting said glide shoes on the outer ends of respective wing members, a rod extending in a direction substantially in the plane of the web, and laterally away from said wing members and from said glide shoes, means interconnecting the inner ends of said wing members and the adjacent end of said rod so that the rod lies in a plane intersecting substantially at right angles with said filter web and with said glide shoes, the assembly of said wing member, said glide shoes, and said rod being constructed and arranged to urge said glide shoes towards each other for maintaining them in cooperative engagement with said tracks, but adapted to release the bead in case of excessive strain occurring laterally outwardly in the direction of said rod, support structure for said rod, which comprises a tubular guide member wherein said rod together with said wing members and glide shoes is shiftable in axial direction, and the glide shoe assembly is turnable about the axis of the rod, and bias means for urging said rod in axial direction away from said filter belt.
 29. In a rotary drum filter apparatus of the endless travelling filter-belt type, said filter belt having beaded edge portion connected to a web of filter material, the bead of each edge portion providing track faces opposite each other and adjacent to the juncture of the bead with the web, a tensioning device which comprises a pair of elongate glide shoes of cylindrical shape adapted to engage said tracks opposite to each other, said glide shoes consisting of a composition material having antifrictional and antifouling characteristics relative to the surface of said bead, a pair of opposedly arranged wing members, means for mounting said glide shoes upon the outer ends of respective wing members, hinge means providing a connection between the inner ends of said wing members, to allow for swinging of each wing member about an individual axis substantially parallel to said glide shoes, pressure means for urging said wing members towards each other and maintaining them in cooperative engagement with said tracks, but adapted to release the bead in case of excessive transverse strain by the glide shoes upon said bead in a direction laterally outwardly therefrom, a rod extending from said hinge connection in rectangular relationship to axis of said hinge connection, and laterally away from the associated edge portion of the filter belt, support means for said rod, which comprises a tubular guide member wherein said rod is shiftable in axial direction, and support structures for said tubular member, constructed and arranged for maintaining said tubular member, said rod, and said glide shoes in cooperative relationship with the associated edge portion of the filter belt, while allowing said rod to shift towards and away from the filter belt, and bias means by urging said rod in axial direction away from said filter belt.
 30. In a rotary drum filter apparatus the device according to claim 29, wherein said hinge means have a single hinge axis.
 31. In a rotary drum filter apparatus of the endless travelling filter-belt type, the filter belt having beaded edge portions connected to a web of filter material, the bead of each edge portion providing track faces opposite each other and adjacent to the juncture of the bead with the web, a tensioning device which comprise a glide shoe assembly having an intermediate body portion, a pair of wing members extending from said body portion opposite each other, and consisting of a resiliently deflectable material, a pair of elongaTe glide shoes connected to the outer ends of said wing members, normally tensioned to engage respective tracks, but allowing said glide shoes to release said beaded edge portions due to resilient deflection and yielding of said wing members in case of excessive transverse strain upon said glide shoes, a rod extending from said body portion in rectangular relationship to said glide shoes, and laterally away from said filter belt, support means for said rod, which comprise a tubular guide member wherein said rod is shiftable in axial direction, and support structure for said tubular member, constructed and arranged for maintaining said tubular member, said rod and said glide shoes in cooperative relationship with the associated edge portion of the filter belt, while allowing said rod to shift towards and away from the filter belt.
 32. The device according to claim 31, wherein there are provided means for adjusting the degree of yieldability of said wing members.
 33. The device according to claim 31, wherein said wing members each have a hinge connection with said intermediate body.
 34. In a rotary drum filter apparatus of the endless travelling filter-belt type, the filter belt having beaded edge portions connected to a web of filter material, the bead of each edge portion providing track faces opposite each other and adjacent to the juncture of the bead with the web, a tensioning device which comprises an assembly of a pair of opposedly arranged elongate glide shoes adapted to engage respective track faces of said bead opposite each other, said assembly being constructed and arranged to urge said glide shoes towards each other and maintaining them in cooperative engagement with the tracks, but adapted to release the bead in case of excessive strain occurring in a direction laterally outwardly away from the associated bead, and in the plane of the filter belt, a rod extending from said glide shoe assembly laterally away from the associated edge portion of the filter belt and in the plane of said belt said rod having an outer threaded end portion, a horizontal externally threaded tubular guide member wherein said rod is shiftable in axial direction, said tubular member having external thread, a support bracket structure comprising an upright portion through which said threaded tubular member extends, a pair of locknuts provided on said threaded tubular member, one on each side of said upright bracket portion for fixing said tubular member in said bracket portion in horizontally adjusted position, adjustable locking means on the outer end portion of said threaded tubular member and providing a stop means adjustable on said tubular member, a stop nut provided on said outer threaded end of said rod, and a compression coil spring surrounding the outer end portion of said tubular member and said rod, confined between said stop means and said stop nut.
 35. In a rotary drum filter apparatus of the endless travelling filter-belt type, the filter belt having beaded edge portion connected to a web of filter material, the bead of each edge portion providing track faces opposite each other and adjacent to the juncture of the bead with the web, a tensioning device which comprises a pair of elongate parallel glide shoes adapted to engage said tracks opposite each other, a shell of resiliently deflectable material having substantially C-shaped cross-sectional configuration with the glide shoes mounted upon the ends thereof parallel to the longitudinal axis of said shell, said glide shoes being biased towards each other by the resiliency of the wing portions of said shell, but effective to release the bead in case of excessive transverse strain upon said glide shoes, a rod extending from the intermediate body portion of said shell, and in rectangular relationship with the axis of shell and said glide shoes, and in a direction outwardly away from said body portion, and laterally away from the associaTed edge portion of the filter belt, support means for said rod, which comprise a tubular guide member wherein said rod is shiftable in axial direction, a support structure for said tubular member; and bias means for urging said rod in axial direction away from said filter belt.
 36. The device according to claim 35, wherein there are provided means effective between the wing portions of said shell, and operable for adjusting a gap between said glide shoes, and thereby adjusting the pressure of said glide shoes upon said tracks.
 37. The device according to claim 35, wherein a transverse tie member extends through the wing portions of said shell with adjustable means provided on said tie member for limiting the movement of said wing members.
 38. The device according to claim 35, wherein said rod is formed with an enlarged end portion conforming to the external contour of the intermediate body portion of the shell, said enlarged end portion being connected to said shell.
 39. The device according to claim 35, wherein said rod is formed with an enlarged end portion adapted to the contour of the intermediate body portion of said shell, and wherein fastening means are provided for detachably connecting said body portion of the shell to said enlarged end portion of the rod. 